Scuba diving (i.e. diving employing Self-Contained Underwater Breathing Apparatus) is a sport of ever increasing popularity. The continual improvement in the equipment employed by sports divers and the resulting improved safety has played an important role in the growth in popularity.
One vital dive safety practice has always been the use of diving lines. Perhaps the most frequent use of diving line is its employment with a dive buoy or marker. Divers have long been required when diving in public waterways and lakes where boat traffic may be present to fly the international diver flag (red field with white diagonal stripe) on the surface of the water above where the scuba divers are diving. The purpose of the diving flag is to warn water craft away from the area where the flag is flying so that divers are not injured when they come to the surface. The importance of the diving flag is understood when it is realized that a scuba diver, although he can hear a motorboat in his vicinity, is unable to tell the direction from which the powerboat is coming because of the high velocity of sound in water. The result is that a scuba diver, who for any number of reasons as for example a low air supply, must return to the surface, is inherently unable to detect an approaching motorboat.
Because scuba divers will often range hundreds of yards to a mile or more in the course of an underwater expedition, it is important that the dive flag attached to a surface buoy is brought along with them. It is in this instance that the sports scuba diver will most often employ a line connecting the diver and the surface buoy with the attached diving flag so that the buoy may follow the diver as he pursues his underwater path. However, a problem arises in connection with the dive marker buoy and the line attaching it to the diver. As the diver traverses his underwater path, his depth will frequently change to match that of the bottom topography. The result will be that he must constantly let out line and wind in line in order to keep the position of the dive marker buoy from drifting away from the spot on the surface directly above his underwater position, because when the diver ascends he creates slack in the line connecting him to the dive buoy.
In addition to the basic problem associated with a dive marker buoy, ice diving, cave diving, and wreck diving are situations in which a diver will normally employ a safety line.
Ice diving is a pastime of scuba divers in northern climates involves the diving in ice-covered northern lakes which are entered from the surface by a hole in the ice. Here a safety line is essential to assure the diver can find his entry hole through the ice which represents his only means for leaving the water when his air supply runs low.
Similarly in cave and wreck diving, the diver's only assured route to the surface is back along the route he has already traversed, and a safety line is essential to assure the diver does not become lost in retracing his path to the surface.
In all the foregoing situations, it is important that the line be taut and that excess slack line not be allowed to accumulate where it may tangle with the diver or obstructions on the bottom and imperil the safety of the diver.
Known reels for use with safety lines and the like employ hand cranks which require two-handed operation by the diver. Other types of reels employ electrical motors and are unsuitable for use underwater. Yet other reels employ coil springs to retract line and are therefore unsuitable for use with diving lines which of necessity must be of considerable length.
Hand-wound scuba diving take-up reels monopolize the use of both of the diver's hands and require considerable effort on the part of the diver both in winding the string and in rewinding it.
Another problem not dealt with by prior reels is the necessity of a scuba diver to combine as many different safety features as possible in each piece of dive equipment.
What is needed is a scuba diving take-up reel suitable for one handed operation with automatic take-up of safety line combining the functions of a writing slate and a maximum rate of ascent indicator.